However, the quandary for the Bears, who lacked a consistent pass rush in 2014, is that most of their defensive linemen are best suited to run a 4-3. The biggest question mark in switching defenses is if veteran Jared Allen could play outside linebacker in a new scheme.

"It's not that I can't do it," Allen told the Chicago Tribune's Brad Biggs this week. "For me, it is a question of what kind of system are we going to run? How do I fit in the system? How do we achieve our goals? These things will play out."

The 33-year-old said he anticipates a switch to a 3-4, even though he's been told nothing firm. However, he also expects to see time with his hand on the ground.

"Lot of sub packages," Allen said. "And when you look at (Fox's Broncos), they were really hybrid on defense so it all depends. For me, I don't worry about that stuff. I'll have the necessary conversations when they come about. I am excited to see how it all plays out."

Allen is due $12.5 million in 2015, all of it guaranteed, which means he will almost certainly be on the Bears' roster, despite coming off one of the worst statistical seasons of his career.

"If I had my choice, my hand is in the dirt and I am on the right side of the line," Allen said. "But I just want to win games."